Author Question: It is possible to hear an approaching train before you can see it by listening to the sound wave ... (Read 109 times)

jho37 · **on:** Jul 28, 2018

It is possible to hear an approaching train before you can see it by listening to the sound wave through the track. If the elastic modulus is 2.0 1011 N/m2 and the density of steel is 7.8 103 kg/m3, approximately how many times faster is the speed of sound in the track than in air? (vair 340 m/s.)
a. 20
b. 5
c. 10
d. 15
e. 25

Question 2

The Young's modulus for aluminum is 7.02 1010 N/m2 . If the speed of sound in aluminum is measured to be 5.10 km/s, find its density (in kg/m3).
a. 11.3 103
b. 7.80 103
c. 2.70 103
d. 29.3 103
e. 1.40 103